JPH10230105A - Operating method for sludge scraper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an operating method by which damage to a sludge scraper by a multi-row driving method is surely prevented without accompanying reduction of operation efficiency. SOLUTION: In the operating method for the sludge scraper, endless chains 31 having flights 4 for scraping sludge are provided in a plurality of precipitation basins 11 arranged side by side and are driven by a driving source 9 thereof. Load torque of one endless chain 31 is detected and operation or stopping of the driving source 9 is performed in accordance with the load torque. In this case, the mean value (Ta) of load torque within a first standard section (ta minute) is calculated. The difference (load variation amount Tb) between the maximum value (T2 ) of load torque within a second standard section (tb second) starting from a point of finish time of the first standard section and mean value (T1 ) is calculated. The driving source 9 is stopped when the load variation amount (Tb) exceeds the set value (T0 ).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of operating a chain flight type sludge scraper having an overload protection device.

[0002]

2. Description of the Related Art In a sedimentation basin for treating sewage and wastewater, for example, a chain flight type sludge scraper is installed in order to scrape sludge deposited at the bottom of the sedimentation basin. In this type of sludge scraper, a flight is attached to a pair of chains connected endlessly at regular intervals, and this flight is slid with a guide rail laid on the bottom of the sedimentation basin, and an underwater shaft, a take-up shaft, It is configured to be driven by a driving device via a driving shaft, to gently move the accumulated sludge, and to scrape to one end of the settling basin. In sewage treatment plants,
Since the above-mentioned settling basins are arranged in a plurality of rows, a sludge scraper is arranged for each settling tank, the drive shafts of the sludge scrapers are directly connected, and these drive shafts are connected by a single drive device. A multi-row driving method for driving is employed.

[0003]

In the sludge scraper described above, an overload protection device such as a shear pin or a torque limiter is provided in order to prevent damage to the flight and its mounting portion. According to this protection device, an overload generated due to a biting of the chain or the like appears remarkably as an increase in the chain tension, and can be detected as a load torque. However, when detecting overload of a plurality of drive trains with a single overload protection device, for example, when one flight interferes with the bracket and overload occurs, the overload is not large, so The torque cannot be detected, and the overload protection device does not operate. That is, when such partial interference occurs, the strength of the chain mounting portion, the flight strength, the safety device setting value, and the chain strength may increase in this order, in which case the operation of the sludge scraper continues. And cause flight damage.

Accordingly, an object of the present invention is to provide an operation method capable of reliably preventing damage to a multi-row driven sludge scraper without lowering operation efficiency.

[0005]

In order to achieve the above object, according to the present invention, a plurality of sedimentation basins arranged side by side are provided.
An endless chain with a flight for collecting sludge and a sludge scraper with its drive shaft are arranged.The drive shafts are connected and driven by a single drive source to reduce the load torque of one endless chain. In the operation method of the sludge scraper that detects and activates or stops the drive source based on the detected load torque, the average value (T) of the load torque in the first reference section [ta (minute)]
₁ ) is calculated and the second starting from the end of the first reference section
The difference between the maximum value (T ₂ ) and the average value (T ₁ ) of the load torque in the reference section [ta (second)] [load change (Tb)]
Is calculated, and the driving source is stopped when the load change amount (Tb) exceeds the set value (T ₀ ).

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the accompanying drawings. 1 is a schematic sectional view of a sedimentation basin in which a sludge scraper is installed, FIG. 2 is a plan view of the same, FIG. 3 is a block diagram showing a control device for carrying out the present invention, and FIG. 4 explains the principle of the present invention. FIG. 5 is a flow chart for explaining an operation example of the present invention. FIG.
, 1, ₁ , ₂ , ... are sedimentation basins, and sludge scrapers 2 are installed along the side walls of the respective sedimentation basins. This sludge scraper 2 has a pair of endlessly coupled chains 3 ₁ , 3 ₂ ,.
Attach flights 4 at regular intervals to
Is slid with a guide rail 5 laid on the bottom of the sedimentation basin 1 so that the underwater shaft 6, the take-up shaft 7, the drive shafts 8 ₁ , 8 ₂ ,.
The sludge deposited on the bottom portion is driven by a driving device 9 through the through-hole and is scraped to one end of the sedimentation basin 10.

[0007] In each sludge scraper 2, both chains 3
_1, 3 _2, it is necessary to rotate in synchronization with ..., drive shaft _81, 82, the pair of ... the driving sprocket wheel 1
, And the drive shafts 8 ₁ , 8 ₂ ,... And the drive sprocket wheel 12 are simultaneously rotated. Underwater shaft 6
Since the sprocket wheels of the take-up shaft 7 and the take-up shaft 7 do not need to be rotated synchronously, the underwater shaft 6 and the take-up shaft 7 are fixed, and the sprocket wheels 10 and 11 are rotatably mounted thereon. The drive shaft 8 of each sludge scraper 2
_1, 8 _2, ... it is connected via a coupling 14, and has a multi-row driving method driven by a single drive unit 9 (see FIG. 2).

In one of the chains 3, a load detecting device (for example, a load cell type torque limiter) 15 for detecting a load torque of the chain 3 is installed. This load detecting device 15 is connected to the driving device 9 via a control device 16 as shown in FIG. This control device 16
Includes an average value calculation unit 16a for calculating an average value of the load torque input from the load detection device 15 within a first reference time, and a load torque calculation unit for a load torque within a second reference time subsequent to the reference time. A change amount calculation unit 16b for calculating a difference (load change amount) between the maximum value and the average value, and a comparison unit 16c for comparing the change amount with a set value input from the reference value setting unit 17; Having.

[0009] With the above configuration, when operating the driving device 9, the driving force is transmitted to the drive sprocket wheel 13 and the drive shaft ₈₁ via a transmission mechanism including a chain 90, the sprocket wheel 10, 11, 12 wound Cheng 3 ₁ travels in the direction of the arrow (Figure 1). Since other sedimentation tank 1 _2, 1 _3, 1 _4, the drive shaft ₈₂ of the installed sludge raking machine, 8 _3, 8 ₄ are directly connected to the drive shaft 8 _1, Cheng 3 _1, 3 _2, 3 ₃ is also run in the same direction. This Each sedimentation tank 1 _1, the 1 _2, ... sludge deposited on the bottom of, asked the take on one end side of the sedimentation tank.

The load torque of the chain during the sludge scraping operation changes as shown in FIG. That is, immediately after the start of the operation of the sludge scraper, the peak value of the load torque appears due to the start-up torque. However, the fluctuation range is small (usually 10 kgf · m or less), and the first reference section [t
a = t ₂ −t ₁ ], the average value of the load torque is T ₁ .
During this normal operation (e.g., time point t _2), when the overload is generated in such a flight interferes with bracket (not shown), and an increase in the load torque of the overload Chen It appears as However, since the sludge scraper is operated at a low speed, the slack of the chain is absorbed, and a slight time lag (tb = t ₃ −t ₂ ) occurs before the overload is detected as an increase in the load torque. . On the other hand, even if no abnormality occurs in the equipment, the load torque may increase due to, for example, an increase in the amount of sediment sludge or the aging of the equipment. Does not appear, but for a long time (tc = t ₄ −
After the elapse of t ₃ ), a peak value (Tp) of the load torque appears.

Based on the above consideration, in the present invention, the sludge scraper is operated by the control device shown in FIG. 3 in the procedure shown in FIG. After first start of operation after a predetermined time, enter the load torque to the average value calculating unit 16a from between the load detection device 15 of the first reference period ta (for example, 30 minutes), where it calculates the average value T ₁ of the load torque (S ₁ ). Next, the second reference section tb (for example, 5 to 10
At between change amount calculation unit 16b of a second), the difference between the load torque during this interval the average value T ₁ (load change amount Ta) was calculated (S _2), the load change amount Ta at comparing unit 16c Set value T ₀
(For example, 30 kg · m) (S ₃ ). And T
If a> T ₀ , it is determined that an overload has occurred due to an abnormality in the device, and the operation of the sludge scraper is stopped. On the other hand, when Ta ≦ T ₀ , the steps S _{1 to} S ₃ are repeated. Thus, according to the present invention, only when an overload occurs due to partial interference or the like in the sludge scraper, it is determined that the load torque fluctuates rapidly, and the operation of the sludge scraper is stopped. It becomes possible.

[0012]

As described above, according to the present invention, the load torque of the chain is detected and the operation of the multi-row drive type sludge scraper is stopped only when a rapid increase in the load torque occurs. Therefore, the operation efficiency of the sludge scraper can be maintained at a high level.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a sedimentation pond provided with a sludge scraper.

FIG. 2 is a schematic plan view of a sedimentation pond provided with a sludge scraper.

FIG. 3 is a block diagram of a control device for implementing the operation method of the present invention.

FIG. 4 is a diagram showing a change over time of a load torque of a chain.

FIG. 5 is a flowchart for explaining an operation example of the present invention.

[Explanation of symbols]

1 ₁ 1 ₂ 1 ₃ 1 ₄ Sedimentation basin, 2 Sludge scraper, 3 ₁
3 ₂ 3 ₃ 3 ₄ chains, 4 flights, 9 drives, 15 load detectors, 16 controllers

Claims (1)

[Claims] An endless chain having a flight for fixing sludge fixed thereto and a sludge scraper having a drive shaft thereof are arranged in a plurality of sedimentation basins arranged side by side. In the method of operating a sludge scraper that drives these with the drive source of No. 1, detects the load torque of one endless chain, and operates or stops the drive source based on the load torque, the first reference section [ta ( Min)], the average value (T
₁ ) is calculated and the second starting from the end of the first reference section
The difference between the maximum value (T ₂ ) and the average value (Ta) of the load torque in the reference section [tb (second)] [the amount of load change (T
b)], and the load change amount (Tb) is set to the set value (T ₀ ).
A method for operating a sludge scraper, wherein the drive source is stopped when the sled is exceeded.